Waec Physics Past Questions For Year 1988

Question 16

The temperature at which the water vapour present in the air is just sufficient to saturate it is called the

waec 1988

• A. ice point
• B. boiling point
• C. steam point
• D. dew point
• E. saturation point

Question 17

0.5kg of water at 10^oC is completely converted to ice by extracting 188000J of heat from it. If the specific heat capacity of water is 4200J kg^-1C^-1, calculate the specific latent heat of fusion of ice.

waec 1988

• A. 9.0 KJ kg^-1
• B. 84.0 KJ kg^-1
• C. 168.0 KJ kg^-1
• D. 334.0 KJ kg^-1
• E. 336.0 KJ kg^-1

Question 18

Which of the following statements about radiant heat is/are not correct?

I. radiant heat cannot travel through a vacuum

II. rough surfaces emit radiant heat more than polished surfaces

III. Dark surfaces absorb radiant heat more than bright surfaces

waec 1988

• A. radiant heat cannot travel through a vacuum
• B. I only
• C. II only
• D. III only
• E. I & II only
• F. II & III only

Question 19

Which of the following best explains a person suffers more severe burns when his skin is exposed to steam than when boiling water is poured onto his skin?

waec 1988

• A. steam is at a higher temperature than boiling water
• B. steam posses greater heat energy per unit-mass than boiling water
• C. steam spreads more easily over a wider area of the skin than boiling water
• D. steam panetrates more easily over a wider area of the skin than boiling water
• E. the specific latent heat of vaporization is released in changing from boiling water to steam

Question 20

In which of the following is the expansion of solids a disadvantage?

waec 1988

• A. the fitting of wheels in rims
• B. fire alarms
• C. the thermostat
• D. the bimatellic thermometer
• E. the balance wheel of a watch